With silver halide photographic materials, it is a frequent practice to color the photographic emulsion layer or other layers for the purpose of absorbing light in a specific wavelength.
When it is necessary to control the spectral composition of the light incident upon the photographic emulsion layer, a colored layer is provided on the side of the photographic emulsion layer on the photographic light-sensitive layer far from the support. Such a colored layer is called a filter layer. If a plurality of photographic emulsion layers are provided, as in a multi-layer color photographic light-sensitive material, such a filter layer may be provided between these photographic emulsion layers.
For the purpose of inhibiting blur in the image caused by the reflection of light which has been scattered during or after the transmission through the photographic emulsion layer by the interface of the emulsion layer with the support or the surface of the photographic light-sensitive material opposite the emulsion layer and the subsequent re-entry of the light into the photographic emulsion layer, i.e., halation, a colored layer may be provided between the photographic emulsion layer and the support or the side of the support opposite the photographic emulsion layer. Such a colored layer is called an antihalation layer. In the case of a multi-layer color photographic light-sensitive material, such an antihalation layer may be provided between the various layers.
In order to inhibit the drop of image sharpness due to the scattering of light in the photographic emulsion layer (generally referred to as "irradiation"), the photographic emulsion layer may be colored.
Most of these layers to be colored comprise hydrophilic colloid. Therefore, these layers normally comprise a water-soluble dye incorporated therein in order to provide color. Such a dye needs to meet the following requirements:
(1) to exhibit an appropriate spectral absorption depending on the purpose; PA1 (2) to be photochemically inert (i.e., to give no chemically adverse effects on the properties of the silver halide photographic material such as sensitivity drop, latent image regression and photographic fog); PA1 (3) to be insusceptible to decoloration or removal by dissolution in the photographic processing procedure which leaves a harmful color on the processed photographic light-sensitive material; and PA1 (4) to exhibit excellent stability over time in a solution or photographic light-sensitive material. PA1 Z.sup.1 and Z.sup.2 each represents a nonmetallic atom group PA1 necessary for forming a benzo condensed or naphtho condensed ring; PA1 R.sup.1 and R.sup.2 each represents an alkyl group; PA1 the plurality of L groups may be the same or different and each represents a methine group, with the proviso that at least one of the plurality of L groups represents a methine group substituted by --OR.sup.12, --N(R.sup.12)(R.sup.13), --SR.sup.12, or --CH(R.sup.14)(R.sup.15); in which R.sup.12 represents an alkyl or aryl group substituted by an acidic substituent, R.sup.13 represents a hydrogen atom or an alkyl or aryl group substituted by an acidic substituent, and R.sup.14 and R.sup.15 each represents a cyano group, a carboxylic acid group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfonyl group or a sulfamoyl group, with the proviso that at least one of R.sup.14 and R.sup.15 contains an acidic substituent; PA1 X represents an anion; PA1 p represents an integer 0 or 1; PA1 r represents an integer 0 or 1; PA1 m represents an integer 2 or 3; and PA1 n represents an integer 1 or 2, with the proviso that when the dye forms an intramolecular salt, n is 1; PA1 R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each represents an alkyl group; the plurality of L groups may be the same or different and each represents a methine group, with the proviso that at least one of the plurality of L groups represents a methine group substituted by --OR.sup.12, --N(R.sup.12)(R.sup.13), --SR.sup.12, or --CH(R.sup.14)(R.sup.15); in which R.sup.12 represents an alkyl or aryl group substituted by an acidic substituent, R.sup.13 represents a hydrogen atom or an alkyl or aryl group substituted by an acidic substituent, and R.sup.14 and R.sup.15 each represents a cyano group, a carboxylic acid group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfonyl group or a sulfamoyl group, with the proviso that at least one of R.sup.14 and R.sup.15 contains an acidic substituent; PA1 X represents an anion; PA1 m represents an integer 2 or 3; and PA1 n represents an integer 1 or 2, with the proviso that when the dye forms an intramolecular salt, n is 1; PA1 R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each represents an alkyl group; R.sup.7 and R.sup.9 each represents a hydrogen atom or a nonmetallic atom group necessary for forming a 5- or 6-membered ring by connecting to each other; PA1 R.sup.8 represents --OR.sup.12, --N(R.sup.12)(R.sup.13), --SR.sup.12, or --CH(R.sup.14)(R.sup.15); in which R.sup.12 represents an alkyl or aryl group substituted by an acidic substituent, R.sup.13 represents a hydrogen atom or an alkyl or aryl group substituted by an acidic substituent, and R.sup.14 and R.sup.15 each represents a cyano group, a carboxylic acid group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfonyl group or a sulfamoyl group, with the proviso that at least one of R.sup.14 and R.sup.15 contains an acidic substituent; PA1 X represents an anion; and PA1 n represents an integer 1 or 2, with the proviso that when the dye forms an intramolecular salt, n is 1; PA1 wherein R.sup.8 in formula (III) is --SR.sup.16, in which R.sup.16 represents an alkyl or aryl group substituted by a sulfonic acid or carboxylic acid group, and R.sup.7 and R.sup.9 are connected to each other to form a 5- or 6-membered ring. PA1 Yield: 0.9 g PA1 .lambda.max: 813.7 nm (H.sub.2 O) PA1 .epsilon.: 1.74.times.10.sup.5 PA1 .lambda.max: 782.0 nm (H.sub.2 O) PA1 .epsilon.: 2.01.times.10.sup.5
As dyes meeting these requirements, many dyes which absorb visible light or ultraviolet rays are known. These dyes are suitable for the purpose of improving image quality in a conventional photographic element which has been sensitized to a wavelength range of 700 nm or less. In particular, triarylmethane and oxonol dyes are widely used in this connection.
On the other hand, it has recently been desired to develop an antihalation and anti-irradiation dye which exhibits absorption in the infrared region for use in a photographic light-sensitive material which serves as a recording material sensitized to the infrared region such as a recording material for recording the output of a near infrared laser.
One of the known methods for the exposure of such a photographic light-sensitive material is an image formation method by a so-called scanner process which comprises scanning an original image to provide an image signal according to which a silver halide photographic material is exposed to form a negative or positive image corresponding to the original image. In this method, the scanner process recording light source most preferably used is a semiconductor laser. The semiconductor laser is a small-sized and inexpensive laser that can be easily modulated. The semiconductor laser is also long-lived and emitts light in the infrared region as compared with a He-Ne laser and an argon laser. Therefore, when a photographic light-sensitive material sensitive to the infrared region is used, a brighter safelight can be used, which advantageously improves the handleability of the material.
However, since there are no appropriate dyes which exhibit absorption in the infrared region and meet the foregoing requirements (1), (2), (3) and (4), especially (3) and (4), it is difficult to obtain an excellent photographic light-sensitive material which is highly sensitive to the infrared region and insusceptible to halation and irradiation. Thus, the properties of the excellent semiconductor laser cannot be made the best use of.
Many efforts have heretofore been made to find a dye that meets the foregoing requirements. Many dyes have been proposed.
For example, tricarbocyanine dyes are disclosed in JP-A-62-123454, JP-A-63-55544, JP-A-64-33547, and JP-A-3-171136 (The term "JP-A" as used herein means an "unexamined published Japanese patent application"), oxonol dyes are disclosed in JP-A-1-227148, melocyanine dyes are disclosed in JP-A-1-234844, tetraryl type polymethine dyes are disclosed in JP-A-2-216140, and indoaniline dyes are disclosed in JP-A-50-100116, JP-A-62-3250, and JP-A-2-259753.
Nevertheless, it is difficult to find a dye that meets all the foregoing requirements.